JPH0418177Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a DC electromagnetic contactor, particularly one having a normally closed contact in which a magnetic blowing effect is performed by a permanent magnet.

Conventionally, this type of DC electromagnetic contactor has a normally closed contact configured as shown in FIG. In the contactor shown in the figure, terminals 12 are first fixed to a base 10 made of plastic. terminal 12
A fixed contact 14 and a magnetic blow-out device 16 are fixed to the screws 18 and 20 by screws 18 and 20, respectively. The magnetic blowing effect 16 includes a permanent magnet 22, a magnetic pole plate 24,
Arc shield 26 made of plastic,
It is composed of a shield support 28, a screw 30 for fixing the magnetic pole plate 24 to the arc shield 26, and a screw 32 for fixing the arc shield 26 and the shield support 28.

Further, a mounting base 34 is provided. A fixed iron core 38 in which a coil 36 is incorporated is attached to the upper part of this mount 34.

A crossbar 40 made of plastic is inserted into the base 10. Furthermore, a movable contact 42, a movable contact receiver 44, a spring receiver 46,
A pressure spring 48, a stopper 50, and a movable contact support 52 are provided. These are engaged with the crossbar 40 by a movable contact support 52 and a stopper 50. A movable iron core 54 is engaged with the lower part of the cross bar 40 by a pin 56 or the like.

An arc box 58 is provided. This is attached to the base 10 with screws or the like. The cross bar 40 is always pushed upward by a tripping spring (not shown) in a normal state, that is, in a non-excited state.

Although not shown in the drawings, there is also a device in which a permanent magnet and a blowout coil are installed together, and a magnetic flux is applied with a normal current to perform a magnetic blowout effect.

Next, the operation will be explained.

When voltage is applied to the coil 36, the movable iron core 5
4 is magnetically attracted to the fixed iron core 38. a crossbar 40 connected to a movable iron core 54;
Movable contactor 42 arranged on this crossbar 40
are also linked. As a result, the normally closed contact generates an arc between the fixed contact 14a and the movable contact 42a, as shown in FIG. The generated arc receives the magnetic flux of the permanent magnet 22 at right angles and is driven outward (arrow A) according to Fleming's left hand rule. Furthermore, the arc rotates in the direction of arrow B and finally hits the surface 26a of the arc shield 26 and is cooled and extinguished.

Next, when the coil 36 is demagnetized, the movable core 54 and the crossbar 40 are returned to their original positions by the tripping spring. As a result, the contact 14a
and 42a come into contact and current I is applied.

The conventional contactor configured as described above has the following drawbacks.

(1) Due to the structure, the final arc length was short and the arc cooling area was small, so the interruption time was relatively long and there was an element of instability.

(2) Since the arc shield 26 is made of an organic material such as plastic, the material carbonizes each time a large current is interrupted and the insulation resistance decreases. Therefore, as the number of interruptions increased, the arc time tended to become longer.

(3) Furthermore, since five screws 18 and 20 must be tightened to construct the porcelain blowout device 16, there is also a drawback that it takes a long time to assemble.

This idea was devised in view of the conventional problems mentioned above, and its purpose was to create a small DC motor that could stably interrupt large currents and greatly increase the number of times it could be interrupted. Our goal is to provide contactors.

In order to achieve the above object, this invention provides a DC electromagnetic contactor having a normally closed contact in which a magnetic blowing effect is performed by a permanent magnet, a permanent magnet, magnetic pole plates installed on both sides of the permanent magnet, It includes an arc shield made of porcelain, and the arc shield is shaped like a box with a bottom in which the surrounding wall and the bottom are integrally formed, and the magnetic pole plate support, the magnetic pole plate, and the magnetic pole are fixed to the fixed contact of the normally closed contact. It is characterized by being attached to the fixed contactor by the elastic action of the plate support.

Hereinafter, preferred embodiments of this invention will be described based on the drawings.

3 to 7 show embodiments of the DC contactor according to this invention.

3-7, a magnetic blowout 60 with an arc shield 62 is provided. This arc shield 62 has a recess 62a in which the permanent magnet 64 is mounted, a recess 62b in which the magnetic pole plate 68 is mounted, and a barrier part 62c. This barrier portion 62c prevents the arc from reducing the insulation of the plastic material around the contacts and further prevents the arc from commutating to the pole plate 66 and terminal 12. Further, the arc shield 62 has a barrier portion 62d for protecting the pressurizing spring 48 from the arc, and an arc cooling surface 62e that covers the fixed contact 68 and the terminal 12 so that the arc is sufficiently extended.

A magnetic pole plate 66 is attached to the recess 62d. Arc shield 62 is attached to fixed contactor 68 . The mounting is performed by fitting the protrusions 70a, 70b of the magnetic pole plate support 70 fixed by caulking or the like into the notches 66a, 66b provided in the magnetic pole plate 66.

A permanent magnet 64 is attached to the recess 62a. The permanent magnet 64 is attracted to the magnetic pole plate 66. An auxiliary permanent magnet 72 is fixed to the fixed contact 68 above the fixed contact 68b by a magnet holder 74 and a screw 76. As a result, the magnetic blowout device 60
is configured.

The curved portion 74a of the magnet holder 74 and the notch 68b of the fixed contact 68 constitute a rotation stopper for the magnet holder 74. The fixed contact 68 is provided with a gas vent hole 68c. The magnetic blowout device 60 configured as described above is attached to the terminal 12 with screws 78, as shown in FIGS. 3 and 4.
At this time, the hole 70c of the magnetic pole plate support 70 and the terminal 12
The screw 80 that fixes the magnetic blower 60 and the fixed contact 68 to the base 10 prevents the magnetic blower 60 and the fixed contact 68 from rotating.

Next, the operation will be explained.

The normally closed contact, which was in the state shown in FIG. 6, generates an arc between the movable contact 42a and the fixed contact 68a, as shown in FIG. The generated arc receives the magnetic fluxes of the permanent magnet 64 and the auxiliary permanent magnet 72 at right angles, and is driven outward (arrow A) according to Fleming's left hand rule. Furthermore, it is stretched and hits the surface 62e of the arc shield 62, where it is cooled. Along with this, the hole 68c of the fixed contact 68
Hot gas is then released from the hole 58-a of the arc box 58, thereby effectively extinguishing the arc.

On the left side of FIG. 3, the arc is similarly extinguished.

Here, the function of the auxiliary permanent magnet 72 will be explained.

Without the auxiliary permanent magnet 72, the arc on the fixed contact 68a side would be driven in the opposite direction of arrow A by the action of the magnetic flux generated by the current flowing through the fixed contact 68 and the magnetic flux generated by the arc. I get used to it. Therefore, as the current increases, it becomes difficult to drive the arc between the contacts in the direction of arrow A.
Therefore, the driving force of the arc due to the current is the permanent magnet 6.
4 becomes larger than the driving force in the direction of arrow A, and the more the firing point of the arc between the contacts is to the left in FIG. 7, the more easily the arc connects between the left and right fixed contacts 68 in FIG. This results in longer shut-off times. In order to counteract this effect, the auxiliary permanent magnet 72 is provided.

Next, when the coil 34 is demagnetized, the movable core 54 and the crossbar 40 are returned to their original positions by the tripping spring. As a result, the contact 42a
and 68a come into contact and current I is applied.

In the above embodiment, the auxiliary permanent magnet 72 is provided above the fixed contact 68, but a magnetic pole plate 82 as shown in FIGS. 8 and 9 may be attached in place of the magnetic pole plate 66 in FIG. However, this may increase the magnetic flux caused by the permanent magnet.

Further, depending on the current value, it may be used without the auxiliary permanent magnet 72. Alternatively, the auxiliary permanent magnet 72 may be provided only on one side, or may be provided on both sides.

As described above, by using inorganic porcelain for the arc shield 62, the decrease in insulation resistance is small and arc resistance can be provided. In addition, as can be seen by comparing Figures 2 and 3, the arc cooling area was increased by elongating the final arc, and a gas vent hole 68c was provided in the fixed contact 68 to effectively utilize the hot gas. By releasing the permanent magnet 72 to the fixed contact 6,
By providing it above 8a, it is possible to cut off a large current in a short arc time and stably with a small size. Furthermore, the number of times that it can be shut off can be increased significantly.

Further, in configuring the magnetic blowout device 60, it can be mounted by utilizing the elastic action of the magnetic pole plate support 70 without tightening screws, making assembly easy and cost reduction possible.

As described above, the DC electromagnetic contactor according to this invention is small in size, can stably interrupt large currents, and can greatly increase the number of times it can be interrupted.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional side view of a conventional DC magnetic contactor.
Fig. 2 is an explanatory diagram of the breaking principle of a conventional DC magnetic contactor, Fig. 3 is a cross-sectional side view of a DC magnetic contactor according to an embodiment of this invention, and Figs. 4 and 5 are detailed views of the magnetic blowout device. , FIG. 6 and FIG. 7 are diagrams of the shutoff principle, and FIGS. 8 and 9 are detailed diagrams of the magnetic blow-off device in other embodiments. The same members in each figure are given the same reference numerals, 10 is the base, 40 is the crossbar, 42 is the movable contact, and 6
0 is a magnetic blowout device, 62 is a permanent magnet, 64 is an arc shield, 66 is a magnetic pole plate, 68 is a fixed contact,
70 is a magnetic pole plate support, 72 is an auxiliary permanent magnet, and 74 is a magnet holder.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a DC magnetic contactor having a normally closed contact in which magnetic blowing is performed by a permanent magnet, a permanent magnet, magnetic pole plates installed on both sides of the permanent magnet, It includes an arc shield made of porcelain, and the arc shield is shaped like a box with a bottom integrally formed with a surrounding wall and a bottom, and a magnetic pole plate support and a magnetic pole plate fixed to a fixed contact of a normally closed contact. and a DC electromagnetic contactor, which is attached to the fixed contactor by the elastic action of the magnetic pole plate support. (2) Utility model registration claim 1, characterized in that the magnetic pole plate support is fixed to the fixed contact of the normally closed contact, and a hole is provided in the support for preventing rotation when the magnetic pole plate support is fixed. DC magnetic contactor described. (3) The DC electromagnetic contactor according to claim 1 or 2, wherein the fixed contact of the normally closed contact is provided with a hole for releasing hot gas. (4) The DC electromagnetic contactor according to any one of claims 1, 2, and 3 of the utility model registration claim, characterized in that the arc shield is provided with a recessed portion for mounting a permanent magnet. (5) Utility model registration claim 1, characterized in that an auxiliary permanent magnet is provided above the normally closed contact.
The DC electromagnetic contactor according to any one of Items 1, 2, 3, and 4.